When a person or organization wants to create a wiki article, the ease with which it can be done depends on what a writer has in mind. There are a number of factors and criteria that must be met before a specific wiki article will be accepted by a popular encyclopedia wiki. For instance, take Wikipedia. Given the popularity of Wikipedia, for those who want to create a wiki page, it is likely their number one choice. Unfortunately, it often difficult to meet all of the criteria for getting accepted on Wikipedia. However, if you want to create your own wiki site, that would be more feasible. A major downfall of that, however, is that nobody is going to care about your wiki, because you would be competing with other larger and wildly popular wikis such as the one above.
If one simply wants to create a Wiki article, it can be done on Wikpedia, as long as it does not involve a person, group, or company for which there is no proof of notability. While encyclopedia wikis seem to have every topic covered, there are subjects of note that have yet to be put up. As such, if you happen to find that a truly notable subject has been excluded from a wiki, there is a good chance that a well written and researched article on the topic may be accepted. However, there are some crucial criteria for acceptance, which must be met to create a wiki article that is accepted. When you create a wiki article, it must be well written; unbiased and balanced in tone; include credible sources that are properly cited; and you should be able to provide evidence of notability. For instance, just because you think that your math teacher is the hottest and greatest thing, and thus, deserves a wiki page, chances are that will not be enough to fulfill the notabililty criterion.
When you intend to create a wiki article, there are several factors to consider. Furthermore, there are many different wikis out there with different rules for getting an article accepted. And because there are so many wikis, there are a many with which one must compete. Thus, in order to create a wiki article that is accepted, one must do their homework. The best advice is to consult a specific wiki and learn about its requirements for acceptance.